A gas turbine engine generally includes a fan and a core arranged in flow communication with one another. Additionally, the core of the gas turbine engine general includes, in serial flow order, a compressor section, a combustion section, a turbine section, and an exhaust section. In operation, air is provided from the fan to an inlet of the compressor section where one or more axial compressors progressively compress the air until it reaches the combustion section. Fuel is mixed with the compressed air and burned within the combustion section to provide combustion gases. The combustion gases are routed from the combustion section to the turbine section. The flow of combustion gasses through the combustion section drives the combustion section and is then routed through the exhaust section, e.g., to atmosphere. In particular configurations, the turbine section is mechanically coupled to the compressor section by one or more shafts extending along an axial direction of the gas turbine engine.
The fan includes a plurality of blades having a radius larger than the core of the gas turbine engine. The fan and the plurality of blades are typically driven by one of the shafts. However, for efficiency reasons, it can be beneficial to have the plurality of blades of the fan rotate at a speed less than a speed at which the respective shaft is rotating. Accordingly, a power gear box is provided in certain gas turbine engines to mechanically couple the fan to the respective shaft in such a manner that allows the fan to rotate at a slower and more efficient speed.
The gas turbine engine additionally includes a lubrication system for providing lubricant to one or more portions of the gas turbine engine, such as the compressor and turbine sections of the core and the power gear box. Typical lubrication systems have a set ratio of lubricant provided at a common temperature to each of the serviced portions. However, the inventors in the present disclosure have found that under certain conditions, it may be beneficial to increase or decrease an amount of lubricant provided to the power gear box or other serviced portions to increase an efficiency of the power gear box or such other serviced portions. The inventors of the present disclosure have also found that under certain conditions it may be beneficial to increase or decrease a temperature of the lubricant provided to the power gear box or other serviced portions to further increase an efficiency of the power gear box or such other serviced portions.
Accordingly, a gas turbine engine capable of controlling certain characteristics of the lubricant provided to the power gear box or other serviced portions, such as flow rate and temperature, would be particularly useful.